A liquid crystal display panel is generally composed of two base plates spaced at a constant distance and liquid crystal sealed in the space between the base plates. The distance of the space is generally referred to as "cell thickness".
In order to obtain a high quality liquid crystal display panel, a uniform cell thickness is primarily required. The uniform cell thickness is usually realized by the following methods:
(1) The base plate is changed to a hard and thick one having a thickness of 3 to 5 mm. PA1 (2) An inside pressure of the liquid crystal display panel is lower than the outside pressure, i.e., atmospheric pressure.
In the method (1), the display panel is heavy, and a displayed image and a shadow thereof result in a double image. In the method (2), if the volume of the liquid crystal is reduced at a low temperature, the inside pressure is further lower and finally it develops bubbles having an almost vaccuum pressure, i.e., "low-temperature bubble" phenomenon.
It is also proposed that a spacer, such as a film, particles, glass fiber and the like, is held between the base plates. If it is desired that the cell thickness is highly uniform, the spacer is used in a quite large amount.
However, if the spacer is used in such a large amount, the cell thickness is held too strongly for the base plates to bend. Bending generally absorbs the volume reduction for the liquid crystal at low temperatures. The amount of bending becomes too small to absorb it, however when the plates are held strongly.
It is therefore desired that the liquid crystal display panel has a uniform cell thickness and does not develop low-temperature bubble phenomenon.